Can not reach the end of waypoint

[yn-mrse]

New Feature

Improve /pure_pursuit so that it can work reliably up to the end of the waypoints.
Correct behavior that can not be reached to the termination point in order to judge the mission complete of decision_maker and precisely control the end of the route.

In the pure pursuit algorithm, to keep the system stability, the distance from the vehicle to the target point must be separated to some extent.
However, at the waypoint termination, the target route becomes short and eventually the system stability can not be secured (#1234). In order to ensure the stability of the system, pull request autowarefoundation/autoware#1235 was made to stop before reaching the end.